Wireless device and key exchange method thereof

Abstract

A wireless device ( 100 ) for exchanging keys with another wireless device ( 200 ) includes a key request module ( 121 ), a key generation module ( 122 ), and a key transfer module ( 123 ). The key request module requests to exchange a key by transmitting a request-key-change frame to the another wireless device. The key generation module generates a new key when the key exchange request is successful. The key transfer module encrypts the new key with a public key of the another wireless device, and transmits a new-key-send frame with the encrypted new key to the another wireless device. A key exchange method is also provided.

1 . A wireless device, for exchanging keys with another wireless device, the wireless device comprising:
 a key request module, for requesting to exchange a key by transmitting a request-key-change frame to the another wireless device;   a key generation module, for generating a new key when the key exchange request is successful; and   a key transfer module, for encrypting the new key with a public key of the another wireless device, and transmitting a new-key-send frame with the encrypted new key to the another wireless device.   
   
   
       2 . The wireless device as described in  claim 1 , wherein the key request module is for transmitting the request-key-change frame to the another wireless device according to a privacy key of the wireless device; the key transfer module is for encrypting the new key with the public key of the another wireless device, and transmitting the new-key-send frame with the encrypted new key according to the privacy key of the wireless device. 
   
   
       3 . The wireless device as described in  claim 2 , wherein the request-key-change frame comprises a beacon type, a digital signature length, and a digital signature; the beacon type indicates a type of the request-key-change frame; the digital signature length indicates a length of the digital signature; the digital signature is a digital signature encrypted with the private key of the wireless device. 
   
   
       4 . The wireless device as described in  claim 2 , wherein the new-key-send frame comprises a beacon type, a key length, a security type, an encrypted key, a digital signature length, and a digital signature; the beacon type indicates a type of the new-key-send frame; the key length indicates lengths of the security type and the encrypted key; the security type indicates a type of the new key; the encrypted key indicates the new key encrypted with the public key of the another wireless device; the digital signature length indicates a length of the digital signature; the digital signature is a digital signature encrypted with the privacy key of the wireless device. 
   
   
       5 . The wireless device as described in  claim 2 , wherein the key request module is also for receiving a request-key-change frame from the another wireless device, and checking the request-key-change frame according to the public key of the another wireless device; the key transfer module is also for receiving a new-key-send fame with an encrypted new key from the another wireless device, and parsing the new-key-send frame to obtain the new key according to the public key of the another wireless device and the privacy key of the wireless device. 
   
   
       6 . The wireless device as described in  claim 1 , wherein the key request module is also for agreeing to exchange a key by transmitting an agree-key-change frame to the another wireless device; the key transfer module is also for informing the another wireless device that the new key has been received by transmitting a new-key-received frame to the another wireless device. 
   
   
       7 . The wireless device as described in  claim 6 , wherein the agree-key-change frame comprises a beacon type, an acknowledgement result, a digital signature length, and a digital signature; the beacon type indicates a type of the agree-key-change frame; the acknowledgement result indicates that the key exchange request is accepted; the digital signature indicates a length of the digital signature; the digital signature is a digital signature encrypted with the private key of the wireless device. 
   
   
       8 . The wireless device as described in  claim 6 , wherein the new-key-received frame comprises a beacon type, an acknowledgement result, a digital signature length, and a digital signature; the beacon type indicates a type of the new-key-received frame; the acknowledgement result indicates that the new key has been received; the digital signature indicates a length of the digital signature; the digital signature is a digital signature encrypted with the private key of the wireless device. 
   
   
       9 . The wireless device as described in  claim 6 , wherein the key request module is also for receiving an agree-key-change frame from the another wireless device, and checking the agree-key-change frame according to the public key of the another wireless device; the key transfer module is also for receiving a new-key-received key from the another wireless device, and checking the new-key-received key according to the public key of the another wireless device. 
   
   
       10 . The wireless device as described in  claim 1 , further comprising:
 a setting module, for setting a media access control (MAC) address and a certification file of the another wireless device, wherein the certification file comprising a public key of the another wireless device; and   an exchange determination module, for determining whether a key exchange is needed.   
   
   
       11 . A key exchange method, for exchanging keys between/among a plurality of wireless devices, comprising:
 transmitting a request-key-change frame from a first wireless device to a second wireless device to request to exchange a key;   transmitting an agree-key-change frame from the second wireless device to the first wireless device to agree to exchange a key;   generating a new key and encrypting the new key with a public key of the second wireless device by the first wireless device;   transmitting a new-key-send frame with the encrypted new key from the first wireless device to the second wireless device;   parsing the new-key-send frame to obtain the new key according to a privacy key of the second wireless device by the second wireless device; and   transmitting a new-key-received frame from the second wireless device to the first wireless device to inform the first wireless device that the new key has been received.   
   
   
       12 . The key exchange method as described in  claim 11 , further comprising:
 using the new key for data traffic between the first wireless device and the second wireless device;   determining whether a key exchange is needed; and   go on to transmit a request-key-change frame from the first wireless device to the second wireless device if the key exchange is needed.   
   
   
       13 . The key exchange method as described in  claim 11 , further comprising:
 setting media access control (MAC) addresses of each other by the first wireless device and the second wireless device; and   setting certification files of each other by the first wireless device and the second wireless device.   
   
   
       14 . The key exchange method as described in  claim 11 , wherein transmitting a request-key-change frame from the first wireless device to the second wireless device comprises:
 transmitting the request-key-change frame from the first wireless device to the second wireless device according to a privacy key of the first wireless device; and   receiving the request-key-change frame, and checking the request-key-change frame according to a public key of the first wireless device by the second wireless device.   
   
   
       15 . The key exchange method as described in  claim 11 , wherein transmitting an agree-key-change frame from the second wireless device to the first wireless device comprises:
 transmitting the agree-key-change frame from the second wireless device to the first wireless device according to the privacy key of the second wireless device; and   receiving the agree-key-change frame, and checking the agree-key-change frame according to the public key of the second wireless device by the first wireless device.   
   
   
       16 . The key exchange method as described in  claim 11 , wherein transmitting a new-key-send frame with the encrypted new key from the first wireless device to the second wireless device comprises:
 transmitting the new-key-send frame with the encrypted new key from the first wireless device to the second wireless device according to the privacy key of the first wireless device.   
   
   
       17 . The key exchange method as described in  claim 16 , wherein parsing the new-key-send frame to obtain the new key according to the privacy key of the second wireless device comprises:
 receiving the new-key-send frame, and parsing the new-key-send frame to obtain the new key according to the public key of the first wireless device and the privacy key of the second wireless device by the second wireless device.   
   
   
       18 . The key exchange method as described in  claim 11 , wherein transmitting a new-key-received frame from the second wireless device to the first wireless device comprises:
 transmitting the new-key-received frame from the second wireless device to the first wireless device according to the privacy key of the second wireless device; and   receiving the new-key-received frame, and checking the new-key-received frame according to the public key of the second wireless device by the first wireless device.   
   
   
       19 . A method for communicating and data-exchanging between a plurality of wireless devices in a protective wireless communication system, comprising:
 requesting by a first wireless device to exchange a key with a second wireless device;   agreeing by said second wireless device to exchange said key with said first wireless device;   generating a new key for exchange by said first wireless device;   encrypting said new key via a certification file of said second wireless device by said first wireless device;   transmitting said encrypted new key from said first wireless device to said second wireless device;   acquiring said new key in said second wireless device by means of parsing said encrypted new key according to said certification file of said second wireless device; and   establishing protective data communication between said first and second wireless devices according to said new key.   
   
   
       20 . The method as described in  claim 19 , wherein said certification file comprises a public key of said second wireless device used to encrypt said new key, and a private key of said second wireless device corresponding to said public key used to parse said encrypted new key.